| Musepack (formerly MPEGplus, MPEG+, MP+) | |
|---|---|
| Filename extension | .mpc, .mp+, .mpp |
| Internet media type | audio/x-musepack audio/musepack |
| Magic number | MPCK, MP+ |
| Latest release | r475 (SV8) August 10, 2011; 14 years ago (2011-08-10) |
| Type of format | Lossyaudio |
| Contained by | MKA/MKV,NUT |
| Extended from | MP2 |
| Open format? | Yes |
| Free format? | Yes |
| Website | www |
Musepack orMPC is anopen sourcelossy audio codec, specifically optimized fortransparent compression of stereo audio at bitrates of 160–180 (manual set allows bitrates up to 320)kbit/s. It was formerly known asMPEGplus,MPEG+ orMP+.
Development of MPC was initiated in 1997 by Andree Buschmann and later assumed by Frank Klemm, and as of 2004 is maintained by the Musepack Development Team (MDT) with assistance from Buschmann and Klemm. Encoders and decoders are available forMicrosoft Windows,Linux andMac OS X, and plugins for several third-party media players available from the Musepack website, licensed under theGNU Lesser General Public License (LGPL) orBSD licenses, and an extensive list of programs supporting the format.[1]
Musepack was developed using theMP2 codec as a starting point, but many features have since been added, including:
Thepsychoacoustic model of MPC is based on MPEG ISO model 2, but is extended by CVD (clear voice detection). The quantization algorithm of the MPC encoder performs spectral shaping of the noise, calledadaptive noise shaping (ANS), in order to overcome the low frequency resolution of thepolyphase quadrature filter bands.
MPC uses theAPEv2 tagmetadata container.[2]
Musepack is mainly optimized for transparent encoding at the "--standard" preset (175-185 kbit/s). Very few optimisations have been made at lower bitrates (like 128 kbit/s). Nevertheless, variouslistening tests have been conducted in which Musepack has performed well at both lower and higher bitrates.[3][4]
Despite being optimized for 100% transparency at moderately high bitrates, MPC has also scored highly on many 128 kbit/s tests. In May 2004, a series ofdouble-blind listening tests[5] (as reported on Slashdot[6]) suggested that Musepack andOgg Vorbis (which was the 1.1 "aoTuV" fork at the time) were the two best available codecs for high-quality audio compression at bitrates around 128 kbit/s, beatingMP3,AAC,WMA, andATRAC.
Listening tests of MPC:
Devices supportingThe Core Pocket Media Player can play MPC. This includes devices runningPalm OS,Symbian OS,Windows,Windows CE andWindows Mobile (Pocket PC). All devices with software audio decoding that are supported byRockbox, including older revisions ofiPod, can also play Musepack files. Playback onRoku Photobridge HD is supported with a plugin.There is a plethora of media players for Android supporting Musepack (among them is the ported Rockbox media player).
Musepack distributes thelibmpcdec library for decoding MPC content. Various plugins have been developed, using that library, including for theXMMS player (onUnix).Asunder and Jack! The Knife allows ripping Audio CD tracks directly into Musepack files.
